1. Field of the Invention
The present invention relates to a coordinate input device, a pad used with the coordinate input device and a communication method for the coordinate input device, and particularly relates to a coordinate input device for inputting coordinates pointed to by a pointer displayed on a screen of a personal computer, a pad used with such coordinate input device and a communication method for such coordinate input device.
2. Description of the Related Art
Recently, electronic money is coming into practical use. Accordingly, experiments involving various types of electronic money are being carried out worldwide. Amongst the various types of electronic money, IC card-type electronic money is one of the types of electronic money which is expected to become of greater use in the near future. The IC card-type electronic money is formed of an IC card having various information stored therein and money is deposited and withdrawn based on the information stored in the IC card.
Further, a number of personal computers and data communications using the personal computers is rapidly increasing. Accordingly, when using the IC card-type electronic money, there is plan to connect home personal computers to a bank host computer for depositing and withdrawing money.
However, in order to access the IC card via personal computers, a dedicated IC card reader/writer is required.
FIG. 1 shows a schematic diagram of an IC card-type electronic money system of the related art. In an IC card-type electronic money system 100, a bank host computer 102 is connected, via a network 101, to an ATM 104 accessible to an IC card 103, to an IC card dedicated terminal 105 and to a personal computer (PC) system 107 having an IC card reader/writer 106 connected thereto. Thus, it is possible to deposit and withdraw money using the IC card-type electronic money system 100.
In the above system 100, in order to access the IC card 103 from the PC system 107, there is a need for the IC card reader/writer 106 connected to the PC system 107.
FIG. 2 is a block diagram showing an IC card reader/writer of the related art. The IC card reader/writer 106 is connected to a personal computer (PC) main body 111 of the PC system 107. The IC card reader/writer 106 includes an interface 112 for interfacing with buses (ISA, PCI), an MPU 113 executing processes according to commands from the PC main body 111, a card interface 114 for interfacing with the IC card 103 and a card unit 115 for connecting with the IC card 103.
The IC card reader/writer 106 accesses the IC card 103 upon receipt of a command from the PC main body 111 and then reads information on the IC card 103 such as the balance of an account.
FIG. 3 is a diagram showing an operation of the IC card reader/writer of the related art. When the power is supplied to the PC main body 111 or an application is started, the PC main body 111 sends an OPEN command to the IC card reader/writer 106 (step S6-1). When the OPEN command is provided in step S6-1, the IC card reader/writer 106 detects whether the IC card 103 has been inserted, and if so, the IC card reader/writer 106 returns a response indicating OK (step S6-2). If not, the IC card reader/writer 106 returns a response indicating NG (step S6-2).
When the PC main body 111 receives the NG response from the IC card reader/writer 106, a message is indicated on the display 112 shown in FIG.1 instructing the insertion of the IC card 103. When the PC main body 111 receives the OK response from the IC card reader/writer 106, an ACCESS command produced during the step of processing an application is sent to the IC card reader/writer 106 (step S6-3).
When the ACCESS command is received in step S6-3, the IC card reader/writer 106 accesses the IC card 103 and executes a process according to the command supplied from the PC main body 111 (step S6-4). The IC card 103 executes a process according to the access from the IC card reader/writer 106 and returns a response (step S6-5).
When the response from the IC card 103 is received in step S6-5, the IC card reader/writer 106 sends a response to the PC main body 111, which response corresponds to the response from the IC card 103 (step S6-6).
The above-described steps S6-3 to S6-6 are repeated so as to read and rewrite information stored in the IC card 103.
The IC card reader/writer 106 may be attached. to the PC system 107 using a built-in file bay of the PC main body 111 or by externally connecting, for example, a special purpose card to an ISA bus slot and to a PCI bus slot.
However, when attached to the PC system 107, the IC card reader/writer 106 occupies input/output ports and bus slots of the PC system 107. Further, by attaching the IC card reader/writer 106 to the built-in file bay, the extensibility of the PC system 107 is reduced.
Also in case where the IC card reader/writer 106 is externally connected to the PC system107, the input/output ports and the bus slots are occupied as in the above case. In addition, a space is required around the PC system 107 for the IC card reader/writer 106 to be placed.
Further, in the system described above, the IC card 106 is only accessible when the PC system 107 is operating. Thus, if a user wishes to make a balance inquiry when the PC system 107 has been turned off, there is a need to turn the PC system 107 on only for making a balance inquiry. Therefore, there are problems such as bad operational efficiency.